Heat insulated fluid container



Oct 25 1965 J. J. RENDos STAI. 3280,@49

HEAT INSULATED FLUID CONTAINER 4 Sheets-Sheet l Original Filed Sept. 2l. 1961 M on 0 J M H m M JOHJ. REA/005 Oct. 25, 1956 J. J. RENDos ETAL. 3,239,349

HEAT INSULATED FLUID CONTAINER Original Filed Sept. 21, 1961 4 Sheets-Sheet 2 Oct. 25, 1966 .1.J. RENDos ETAL. 323,@49

HEAT INSULTED FLUID CONTAINER Original Filed Sept. 2l. 1961 4 Sheets-Shea?l 5 /N l/E N TORS Oct. 25, 1966 .1.J. RENDos ETAL. 3,280,349

HEAT INSULATED FLUID CONTAINER Original Filed Sept. 21, 1961 4 Sheets-Sheet 4 JOH/V J. :QE/V005 M/CHEL JORDAN /NVENTORS f ym@ W y AGE/VT United States Patent O 3,280,849 HEAT HNSULATED FLUID CNTAINER .lohn il. Rendus, Millington, and Michael Jordan, Union,

NJ., assignors to Air Reduction Company, Incorporated, New York, NSY., a corporation of New York Continuation of abandoned application Ser. No. 139,800,

Sept. 21, 1961. This application Feb. 15, 1965, Ser.

S Claims. (Cl. 13S-149) This application is a continuation of our prior copending application S.N. 139,800, led September 2l, 1961, now abandoned.

This invention relates to heat insulated containers for fluids at high or low temperatures, and more particularly to prefabricated containers in the form of unit sections which can be easily joined together at the place of installation to form a continuous conduit or vessel `of any desired length.

Fluid transfer lines for carrying very cold or Very hot fluids are known in which the thermal expansion of the conduit carrying the fluid is very appreciable so that devices such as flexible expansion sections and sliding joints sealed by metal bellows or the like are needed to retain the liuid and at the same time allow the conduit to expand `and contract, particularly during intermittent use.

The fluid container herein described avoids the need for flexible sections, sliding joints and sealing means therefor by being made of a substance, such as Invar, a nickel steel containing about 36 per cent nickel and having no material thermal expansion or negligible thermal expansion over a wide range of temperatures such las are encountered between ordinary ambient temperature and the temperature of cryogenic liquids, such as liquid oxygen, or between such ambient temperature and the temperature of molten solids commonly transported through pipelines.

Fluid transfer lines are known which may be prefabricated and separately evacuated as unit sections to be assembled in place to form a pipeline. Some of these have the disadvantage that the sections are partly telescoped Where they join, so that if later a section must be replaced several lengths or the entire line must be dismantled as there is insufficient room to withdraw one section from the line. Other have the disadvantage that adjacent sections must be welded or bolted together at the place of installation or a portion of the inner conduit is exposed directly to the ambient temperature at either end of the section.

Further, in order to reduce the heat leakage at the juncture of adjacent sections cumbersome arrangements have been employed requiring awkward assembly Iand the necessity of evacuating the interior of connecting fittings in the field, usually with uncertain or unsatisfactory results.

The type of line section herein described avoids these difficulties by providing substantially coplanar or flush ends for both the inner tube or conduit and the outer casing so that adjacent sections may be coupled together in butt joints by means of an external clamp and the joint sealed by an internal gasket such as an O ring, no part of the inner tube being anywhere exposed, and no welding or evacuation of the joint being needed at the place of installation.

A combination end seal and spacer or joint element is provided at each end of the line section, especially constructed to minimize heat transmission between the inner tube and outer casing, to facilitate joining adjacent sections and to extend the minimum length of section at which the necessity of an intermediate spacer must be taken into consideration. Advantageously the end seal member is of annularly corrugated construction, desirably ICC extending the thermal barrier of the evacuated interspace as much as possible at the ends of the sections and furnishing a maximum length of heat conductive path lat such end sealing means.

Accordingly, an object of the invention is to avoid the necessity for providing expansion joints or glide joints in pipelines composed of a plurality of pipe sections joined together. Another object is to provide pipe sections which are easily `assembled or dissambled and which afford an interconnection between the successive sections of exceedingly `low heat discharge without the necessity of cumbersome fixtures yor the drawing of a vacuum at the fitting at the time of installation.

Another object is to lprovide a double-Walled pipe section with an evacuable space between the walls and having a minimum of heat transmission through the vacuum seal, which latter necessarily provides some thermal communication between the opposing walls.

Another object is to faciltate the placement of insulation in the space between the walls of a double-walled conduit during the manufacture of prefabrication of a unit section of the conduit.

A further object is to reduce losses of heat or of refrigeration during periods in which the inner walls yof a double-Walled conduit or vessel are being warmed up or cooled off as during intermittent use of the conduit or vessel.

A further object is to reduce the time required to evacuate the space between the walls of a double-walled container when such space is partially occupied by solid insulating material.

A feature of the invention is the use of a material having a minimum thermal coetiicient of linear expansion, such `as Invar, for the inner wall of the conduit which carries the iiuid to be transported.

Another feature is an improved vacuum seal between the inner and outer walls of the conduit or vessel particularly adapted for use at the ends of `a pipe section to facilitate the joining together of two adjacent pipe sections.

Another feature is an improved arrangement for inserting and retaining a cylindrical layer or layers of insulation in a space between two concentric sylindrical walls of a conduit or vessel without completely lling the said space.

A further feature is an improved means of joining together two sections of double-walled piping using a V- clamp to press together the outer walls of the adjacent sections as well as to seal the joint between the inner walls by compressing a gasket or an O-ring of durable, inert, resilient material, such as neoprene, Buta-N, or Teflon, between flanges mounted upon the outer surfaces of the respective inner walls of the adjacent pipe sections.

A further feature is compression of the insulation within the external corrugations of the end seal when adjoining line sections are clamped together.

Other objects, features and advantages will appear from the following more detailed description of an illustrative embodiment of the invention, which will now be given in conjunction with the accompanying drawings.

In the drawings,

FIG. l is an elevational view showing the general external appearance of a transfer line, in accordance with one form of our invention;

FIG. 2 is a diagram showing the relationship of parts FIG. 2A and FIG. 2B which parts together form a longitudinal view, partly in section, of -a transfer line of the type shown in elevational view in FIG. l;

FIG. 3 is a cross-sectional view of the transfer line of FIG. l taken at the line 3 3, before the placing of `an insulating filling;

FIG. 4 is a cross-Sectional View taken at 4the same line 3 3, after the placing of said filling;

FIG. 4A is a fragmentary longitudinal sectional view as in FIG. 2A, showing the unclamped c-ondition of the abutting ends of two line sections;

FIG. 5 is a cross-sectional view taken at the line 5 5 of FIG. 1 after the placing of said lling;

FIG. 6 is a cross-sectional view taken at the line 6 6 in FIG. 1, showing layers of insulation and radiation shields held in place by a helical spring;

FIG. 7 is -a cross-sectional view taken at the line 6 6 in FIG. l assuming the layered insulation to be replaced by particles of insulation filling the space between adjacent walls;

FIG. 8 is an elevational view, partly broken, showing a method of winding layers of insulation and radiation shields upon a compressed helical spring;

FIG. 9 is a sectional view of .the arrangement of FIG. 8 taken at the line 9 9 as it appears after several layers of insulation have been wound over the spring;

FIG. l0 in a cross-sectional view taken at the line 10- 10 in FIG. 1;

FIG. l1 is a sectional view of an assemblage of several alternate layers of insulation and radiation shields wound over the outer surface of the inner .tube of a transfer line such as that show generally in FIG. 1; and

FIG. l2 is a plan view, partly in section, of an alternative form of the invention, in which the transfer line has an outer casing of substantially uniform outside diameter.

Referring to FIG. 1, .there is shown the general external appearance of one illustrative embodiment of a transfer line constructed according to the teaching of the invention. The line comprises a plurality of separable sections or lengths of the .transfer line structure coupled together by means of clamps. One full length is shown with adjoining lengths on either side shown in fragmentary represent-ation. A portion of the outer casing of an adjoining lengh at the left is shown at 20. Attached to, or integral with, the casing member 20 is a bell-shaped terminal casing member 22. Opposite the casing member 22 is a similar member 24 attached to, or integral with, an outer casing member 26 of the full length pipe or transfer line represented in the figure. Each length of transfer line contains an inner tube for carying the fluid to be transported, together with vacuum seals, spacing members, insulation, etc., not all shown in FIG. 1 but appearing in detail in the subsequent figures. The casing members 22 and 24, together with their respective inner parts are abutted at their outer ends and secured by a clamp or coupling member 28.

The typical central casing member 26 has mounted thereon a suitable vacuum valve 30 for use in evacuating a space inside the member 26 between this member and the outer surface of the inner tube, the valve assembly including a valve handle 32 and an inlet conduit 34 to which a vacuum line leading to a vacuum pump may be attached.

Attached to, or integral with, the member 26 is a bellshaped terminal member 36. Opposite ,the casing member 36 is a similar member 38 attached to, or integral with, an outer casing member 49 of the next length of transfer line to the right shown in fragmentary representation. The casting members 36 and 38, together with their lrespective inner parts are abutted at their outer ends and secured by a clamp or coupling member 42.

In general, the central portion of a line Section will be longer than the bell-shaped end portions, lalthough any length may be used as required under given conditions. For purposes of illustration and to conserve space in the drawing, FIG. 1 shows the central portion shorter than the end portions.

In some cases, the member Z6 may be of sufficient diameter, equal to the diameter of the terminal members 24 and 36 and these members may be replaced by a single 4 outer tube of uniform diameter, as illustrated in FIG. l2.

In FIG. 2A, the inner tube inside the casing members 20 and 22 is shown at 44. The inner tube inside the casing members 24, 26 and 36 is shown at 46. The tubes 44 and 46 are preferably made of Invar in order to minimize change of length due to heating and cooling While the tube is in intermittent use. The use of such material makes it possible to avoid the necessity for flexible sec tions, sliding joints and bellows structures in connecting together adjoining lengths.

A combination spacer and vacuum-tight end seal is provided between the outer surface of the inner tube and the inner surface of the casing at each end of a length of the transfer line. For this purpose, a conical member 48 is fastened to the outer surface of .the inner tube 46 close to the end of the tube 46, at `the left-hand end as shown in the figure. A conical member 48 flares toward the right. A second conical member 50, flaring toward the left, is fastened to the right-hand end of the member 48 and extends to-ward .the left nearly as far as the left-hand end of the tube 46. A third conical member 52, flaring l toward the right, is fastened to .the left-hand end of the member Sil and extends to 4the right about as far as the junction of the members 48 and 5t). A fourth conical member 54, flaring toward the left, is fastened to the right-hand end of the member 52 and extends to the lefthand end of the casing member Z4 and is fastened at its left-hand end to the member 24. While four conical members are shown, in some cases two may sufllce, in which case the left-hand end of member 5t) may be fastened to casing member 24 at or near the left-hand end of this member. In other cases, six or more conical members may be used, the outermost conical member being fastened to casing member 24 at or near the left-hand end. The Ifastenings of all these coni-cal members should be made vacuum-tight and the assembly as a whole should be relatively rigid to maintain a substantially fixed spacing between :the inner tube 46 and the casing member 24. FIG. 3 is an end view of the assembly comprising the tube 46, the casing 24 and the conical members 50, 52, 54.

While an even number of conical members are described and shown, an odd number m-ay be used if desired, although in most cases an even number will be .preferred las providing generally more complete vacuum jiacketing .and less Idirect exposure of the inner tube to the surrounding medium.

The casing members 20, 22, 24, 26, 36, 38, 40, and the various conical members are preferably made of stainless steel. The conical members may be fastened in place by any suitable means, such as silver soldering or welding. Similar assemblies of conical members are provi-ded at each end of each length of transfer line, t'he assembly at one end being constructed like a mirror image of the assembly at the other end of the same length of line. As shown in FIGURE 2A, for example, the conical members make up an end supporting tand sea-ling assembly of such proportions that the depth of corrugation along (parallel to and adjacent) the longitudinal axis of the .length is at its maximum depth at least several times the spacing between adjacent corrugations, thereby providing a relatively long path for conduction of heat from the outer casing to the inner tube.

At one end of the tube 46, the left-hand end as shown in the figure, there is fastened to the outside of the tube a sealing member retaining flange 56. Near the adjoining end of t'he tube 44, there is fastened to the outside of the tube a complementary yflange 58. Between the flanges 56 and 58 there is provided space yfor an O ring sealing member preferably of an inert, durable, resilient material such as neoprene, Buta-N, or Teflon, to seal the joint between the tubes 44 and 46. Similar sealing structure is provided on both sides of each joint of two adjoining inner tubes.

The spaces between the conical members 48 and 50 `and between the conical members 52 and S4 are preferably filled with some suitable insulating material such as Gem Foam, a polyurethane foam, which may be poured in place and allowed to har-den, or rock wool or silicone powders which may be packed within the convolutions if the cones. The insulation preferably partially surrounds the flange 56 and, when clamped, forms a flat surf-ace 62 perpendicular to the longitudinal axis of the tube 46 near the end of the tube. FIG. 4 shows an end view of the tube 46, the flange 56, an O ring 60 in place upon the flange 56, `and the outer surface 62 of the insulation. It will be noted fro-m FIG. 2A that the insulation extends beyond the left-hand end of the casing member 24.

It will be noted th-at the tightening of the V-clamp draws the adjoining casing and seal members together. In general, there will be sufcient play W-hen a single section of line is unclamped so that the section can readily be removed and another substituted, even though the llanfges 56 of one section extend slightly into the inner space of the adjoining section when in the clamped position.

FIG. 5 shows in cross-section the insulation in the outside corrugations formed by the conica-l members, which insulation preferably extends :all the way to the line of fastening together of the inner ends of the adjacent conical members.

The coupling 28 preferably comprises a V-shaped band 64 attached to, or integral with, a flat band 66, the flat band having portions or anges 68, 70 bent at `an `an-gle Vas shown in FIG. l, which flanges rnay be drawn toward each other by means such as a bolt 72 and a nut 74. It will be noted that tightening the coupling member 28 compresses the gasket or O ring 60 due to the general rigidity of the structures and presses the insulation surface 62 against its opposite insulation surface Within the casing member 22, thus not only substantially lilling with insulation the annular space between the inner tube and the casing in the neighborhood of the joint, but also securely fastening together the radjoining casing members 22 and 24 and sealing the joint between the inner tubes 44 and 46. The insulation at the joint retards heat transmission over a direct path between the inner tube and the outer casing.

This thermal barrier against heat leakage over a direct path between the inner tube and outer casing includes the extension of the evacuated inner space substantially to the distal ends of the inner tubular conduit and outer casing as provided by the desirable feature of construction of the axially extending corrugated member. It will be readily apparent that radial heat leakage yacross the corrugated member will be substantially reduced as compared to other conduit structures, since the evacuated inner sp-ace extends to the ends, as yjust described in the lines above, providing a short circuiting of any direct path of heat leak in the conduit, `and since at the same time the path of heat leak across the corrugated member is greatly extended as the result of the shape of the corrugated member, las viewed for example in FIGURES 2A and 2B. In addition, the filling of a -low heat conductivity material in the external depressions formed in the corrugated end seal will further reduce the radial heat leakage by reducing free air space. The provision of the latter low conductivity material, it will be seen, is desirably incorporated in the externall recesses of the corrugated member to provide a substantially dat end face, whereby adjacent sections, when brought together, `are substantially free of intervening air spaces. This construction affords an insulating effectiveness in this region of ya very high degree which, at the same time, however, does not require evacuation of the minimized inner space between abutting sections in order to accomplish the improved degree of insulation. In the unclamped condition, as shown in FIG. 4A, the end face of the body of insulation in the external recesses of the corrugated member .may be slightly convex so that, when clamped, the adjoining bodies of insulation will be firmly pressed together to form a tight seal.

The vacuum space between the inner tube and the outer casing in the main central portion 26 of the length of transfer line is preferably provided with insulation either partially or wholly filling the space. For intermittent service, a partial filling is preferable, with the insulation spaced apart from the inner tube so that the mass of insulation will not have to be warmed or cooled during each period of use. For continuous service, the space may be completely filled, thereby -avoiding the need for special supporting arrangements for the insulation, or insulation may be mounted upon the outer surface of the inner tube as described hereinafter. In some cases, it may be found desirable to omit the insulating material altogether.

FIGS. 2A and 2B show the case in which the insulation comprises alternate layers of aluminum foil and glass wool resiliently held -against the inner surface of the outer casing member 26 by means of an outwardly pressing helical spring. In these figures, layers of glass wool are shown at 76, and 84, layers of alumnium foil at 78 and 82, land the helical spring at 86, the spring being in direct contact with the layer 76 and the layer 84 being pressed against the inner surface of the causing member. the layers of aluminum foil serve as multiple shields for minimizing transfer of heat by radiation, while the glass wool serves to space and insulate adjacent radiation shields. It will be noted that there is a space between the spring 86 andthe outer surface of the inner tube 46. Tlhis space avoids direct heat conduction between the inner tube and insulation and radiation shields Iand also Ifacilit-ates rapid evacuation of the vacuum space by making it unnecessary to draw out air through pores in the insulating material.

FIG. 6 is a cross-sectional view of the insulated line with the insulation held in position by the helical spring 86.

FIG. 7 is a cross-sectional view of an insulated line in which the interspace is entirely filled with insulating material. In this case there is no retaining device to hold the insulation in place as no such support is needed. It will be note-d that in this case the insulating material need not be laminated but may be packed in either tightly or somewhat loosely or may be poured in and allowed to harden, or any other suitable arrangement may be ernployed, according to the properties of the insulating material.

In the case of using the laminated insulation spaced from the inner tube, the helical spring is preferably made of sufficient outside diameter that when in place it will exert an outward pressure against the insulation to hold the insulation securely in place unde-r compression.

A preferred method of installing the insulation under compression from the helical spring is to first twist the spring to contract its diameter and then to wind the insulation over the spring while retaining the spring in its twisted condition. The outside diameter of the outer layer of insulation as wound upon the twisted spring should be slightly less than the inside diameter of t'he casing member in which the insulation is to be placed so that the spring and the over-Wound insulation may be inserted inside the casing member. A-fter insertion, the means holding the spring in twisted condition may be released and removed, thereby allowing the spring to expand and hold the insulation resiliently in place against the inner surface of the casing member 26.

FIGS. 8 and 9 illustra-te a method of holding a helical spring to a contracted diameter and applying layers of insulation and metallic foil thereto preparatory to inserting the spring and overwindings into a cylindrical casing member. A cylindrical metal form 94 is provided, which may be a hollow tube as shown in elevation in FIG. 8 and in cross-section as shown in FIG. 9. The outside diameter of the form 94 is suciently smaller than the inside diameter of the helix of the spring 86 to provide the desired amount of contraction of the spring dia-meter to give the desired outward pressure after release of the spring and to obtain the necessary clearance for inserting the overwound spring into the casing mem-ber 26. The length of the fonm 94 should be at least as great `as the extended length of the spring when the latter has been twisted.

To contract the spring 86, one end thereof is first fastened to the form 94 near one end thereof .as by soldering at 96. The spring is then twisted by means of pliers or otherwise to .decrease its diameter until the spring is in contact with the form 94 along the entire length of the spring, The free end of the spring is then fastened to the form 94 as by soldering at 98.

A sheet of insulation 100, such as glass wool, prefera-bly, although not as shown in FIGURE 8, a little nar rower than the axial distance between the solder points 96, 9S is then wound once around the spring 86. The sheet of insulation 100 is preferably a little narrower than the axial distance between the solder points, as just described, in order to give access to the solder points for release of the spring, as discussed in detail in the next full paragraph. A sheet 102 of heat reflective material, such as aluminum foil of approximately the same width as the sheet of insulation and long enough to equal the circumference of the outside of one turn of the insulation is l-aid upon and wound around the insulation as shown in FIGS. `8 and 9. The insulation alone is Wound once more around the spring and a second sheet 104 of reflective material is laid on and wound around the insulation 100 as shown in FIG. 9. Other sheets of reflective material may be added and covered with the winding of insulation in similar fashion as desire-d, to make up the total thickness of insulation an-d reflective material needed. The outer end of the sheet 100 may be fastened in place in any suitable manner after trimming the sheet to the required length.

The assembly of form, spring, insulation and reflective material may then be inserted into the tubular casin-g member and the solder may be melted to release the spring which will then expand, clamping the insulation and reflective material against the inner surface of the easing member 26. The form 94 is likewise released when the spring expands so that the form may be withdrawn.

It is preferable that the several sheets of reflective material are not in contact with one another in the assemblage of insulation and foil, thereby avoiding any continuous conductive path over the foil between the inner and outer layers while retaining the full heat reflective function of the foil.

Alternatively, a body of laminated insulation, or a body of nonlaminated insulation, cut to the proper size and shape may be laid upon the spring 86 and inserted in place in a manner similar to that described above for the insertion of the alternate layers of insulation and metalli-c foil.

FIG. 2B shows an illustrative placement of the vacuum valve 30, 32, and vacuum connection 34 for use in evacuating the line length at the factory or shop during fabrication of the line or subsequently when re-evacuation may be required as for instance due to slow leakage. The vacuum fixture assembly is preferably placed near the center of the length of the casing member 26 so that advantage may be taken of an interruption of the insulation to provide not only access space for the vacuum connection but a place to locate a radial spacer 88 in case the length of line is so long that the combined end spacers and vacuum seals formed by the conical members 48, 50, etc. are not sufcient and intermediate support is desirable. In some cases it may be desirable to limit the length of prefabricated line segment to a length not requiring intermediate spacers. In general, one or more intermediate spacers may be provided as required, depending upon the flexibility of the tubular members'. An

Vvent unrol-ling of the assemblage.

illustrative form of a suitable spacer is shown .in FIGS. 2B and 10, having a square shape with a cross-like central cut-out portion 90. The spacer 88 makes contact with the casing 26 at the four outer corners only, and makes contact with the inner tube 46 only at four inner corners of the central cut-out portion.

In case the liquid transfer line is to be used in continuous or substantially constant temperature service, that is, where material to be moved is continually present in the line, the laminated insulation, if used, is preferably wound upon the -outer lsurface of the inner tube, since this is more readily accomplished and it is not necessary to expose the insulation to alternate period of heating and cooling. In this case, the supporting spring 86 and form 94 are not necessary and may be dispensed with. The method :of winding the insulation and radiation shields upon the inner tube 46 is otherwise the same as is illustrated in FIGS. 8 and 9, the sheet of insulation 100 being wound initially one full turn about the tube 46, whereupon the sheet 102 of heat reflective material is applied over the tu-rn of the sheet as above described. The winding continues as illustrated in FIGS. 8 and 9, the result being the laminated assemblage of insulation and radiation shields as illustrated in pla-ce upon the inner tube as shown in FIGS. 11 and 12. The outer layer of the assemblage of insulation and radiation shields may be fastened in place by any suitable meansl which Will pre- Alternatively, a body of laminated insulation, or a body of nonlaminated insulation, cut to the proper size and shape may be mounted upon the outer surface of the inner tube in any suitable manner.

FIG. 12 shows how a length of transfer line may be assembled from an inner tube of uniform outside diameter and a plurality of outer shell elements of uniform inside and outside diameters, together with an elbow, spacers, insulation, getter cartridges, vacuum valve assembly and butt joint connecting elements.

In FIG. 12, the inner tube comprises a section having a curved portion 112 for providing an elbow formation and a straight section 114. An elbow shell element 116 surrounds the curved portion 112 and is spaced therefrom by means of a spacer 11S held in place by annular members 120 and 122, one of which, say 120, may be xedly attached to the inside of the element 116. Mounted upon the inner tube member 110 are an insulation assembly 124, a spacer 126 and a getter cartridge 128. On the inner tube member 114 are similarly mounted insulation assemblies 130, 132, 134 and 136, spacers 138, 140, 142 and 144, and a getter cartridge 146. Butt joint connecting elements 148 and 150` are provided, in which annularly corrugated member 152 is fxedly attached, as by welding, to connecting element 143 and annularly corrugated member 154 is xedly attached, as by welding, to connecting element 150. A vacuum valve assembly is provided in an outer shell element 156. Additional outer shell elements 158, and 162 are also provided.

The transfer line of FIG. 12 may be assembled by the following procedure. The bend 112 having been made in the tube 110, the insulation assembly 124, spacer 126, and cartridge 128 are placed in position )on the tube 110. On the tube 136 there are placed in position the insulation assemblies 130, 132, 134, 136, the spacers 138, 140, 142, 144 and the cartridge 146. The elbow shell element 116 is then slid into position over the bend 112 and held in place by inserting Ithe spacer 118 against fthe retaining ring 120 and securing the spacer in position by means of retaining ring 122.

The inner tubes 110 and 114 may now be welded in a butt joint at 164 and this joint tested for vacuum tightness.

The remaining louter shell elements may now be slid in place over the vspacers and fastened as by welding or other suitable means, to the elbow shell element 116 and to one another .in order, the element 158 being fastened to the elbow shell element 116 as in a butt joint 166, the joint element 148 Ito the shell element 158 in a joint 168, the element 160 to the elbow shell element 116 in a joint 170, the element 156 to the element 160 in a joint 172, the element 162 to the element 156 in a joint 174, and the joint element 150 to the element 162 in a joint 176. Finally, the corrugated element 152 may be attached to the outer end of the inner tube 110 at a joint 178 and the corrugated element 154 to the outer end of the inner tube 136 at a joint 180 and the vacuum space tested for vacnum tightness with the aid of the vacuum valve assembly. Flange members 182 and 184 may be provided as part of corrugated members 152 and 154, respectively, to receive gaskets or O-rings to serve as seals be-tween sections of inner tube as described in connection with the line shown in FIG. 2-A.

Straight lengths, or lengths containing T joints may be fabricated and assembled in manner generally similar to that described in connection with FG. l2, omitting the elbow tting and substituting a T-joint fitting where required. The prefabricated and assembled length may have insulation applied to the external portions of the corrugated joint elements as in the case of the embodiment shown in FIGS. 2-A and 2-B. Each of these lengths of transfer line constructed in accordance with the teachings of the invention has substantially flush ends which facilitate the connection of a plurality of lengths into an extended transfer line or the like, and which facilitate removingr any length from the whole for repair, replacement, or inspection without dismantling adjacent portions of the line.

It will be noted that in the type of line section shown in FIG. l2 the use of spacers is generally advantageous and facilitates the placement of the outer casing members during the assembling process.

While the invention has been illustrated herein as applied to a transfer line or pipe line, portions of vessels or containers of other shapes and sizes may be fabricated making use of similar forms of construction so as to provide inner compartments for storage or transport of cold or hot materials, together with suitable vacuum jackets, properly sealed, spaced and insulated, and the portions joined together at the place of installation, similarly to the examples of the transfer line or pipe line.

In some instances, the prefabricated sections may be welded in the field to other similarly prepared sections instead of clamped together, in which case, however, the welding in the field need not be vacuum-tight, inasmuch as the sections themselves are vacuum-tight as brought to the place of installation. A butt weld will generally be suitable for this purpose.

While illustrative forms of apparatus in accordance with the invention have been described and shown herein, it will be understood that numerous chnages may be m-ade without departing from the general principles and scope of the invention.

We claim:

1. A vacuum jacketed conduit extending along a longitudinal axis for carrying a fluid of temperature substantially divergent from ambient comprising adjacent unit sections each having an imperforate unitary rigid inner tubular element, an outer casing element spaced from and of substantially the same length as said inner element, said casing element surrounding said inner element and being substantially coextensive in length therewith, said inner and outer elements terminating substantially coplanarly at the ends, and substantially rigid imperforate combined spacing and closure means of effectively low thermal transmission properties fastened to each end of said inner element and the corresponding end of the said outer element so as to fasten together said inner and outer element in substantially fixed spaced relation to each other and so as to seal the space between said inner and outer elements, said space being evacuated so as to provide a vacuum therein, said spacing and closure means comprising a corrugated member having at least one corrugation extending along said longitudinal axis, the maximum depth along said longitudinal axis of corrugation of said corrugation being lat least several times as great as the maximum radial distance across said corrugation, thereby providing a relatively long path in order to minimize transfer of heat by conduction from said outer casing element to said inner tubular element, said spacing and closure means defining a longitudinally exteriorly facing cavity.

2. Apparatus according to claim 1, said inner tubular element composed of a substance substantially free from thermal expansion over a temperature range extending from ambient temperature to the widely different temperature of a fluid to be carried by said conduit member.

3. A vacuum jacketed conduit member extending along a longitudinal axis comprising an imperforate unitary rigid inner tubular element composed of a substance substantially free from thermal expansion over a temperature range extending from ambient temperature to the widely different temperature of a uid to be carried by said conduit member, whereby said inner element is substantially constant in length whether heated or cooled within said temperature range, an outer casing element spaced from and of substantially the same length as said inner element, said casing element surrounding said inner element and being substantially coextensive in length therewith, said inner and outer elements terminating substantially coplanarly at the ends, and substantially rigid imperforate combined spacing and closure means of effectively low thermal transmission properties fastened to each end of said inner element and the corresponding end of the said outer element so as to fasten together said inner and outer elements in substantially xed spaced relation to each other and so as to seal the space between said inner and outer elements, said spacing and closure means comprising a corrugated member extending along said longitudinal axis of more than one corrugation, at least one corrugation of axial length along said longitudinal axis at least several times as great as the maximum radial distance across said corrugation, thereby providing a relatively long path in order to minimize transfer of heat by conduction from said outer casing element to said inner tubular element, said space being evacuated so as to provide a vacuum therein, said spacing and closure means defining a longitudinally exteriorly facing cavity at each end of said conduit member, and insulating material disposed in each exteriorly facing cavity, whereby a single conduit member can be removed from a line of said conduit members joined at said coplanar terminations.

4. Apparatus according to claim 3, said corrugated member comprising a plurality of hollow conical members of substantially equal axial length, a first of said members fastened to the inner tubular element, the minimum internal diameter of said rst of said members being substantially the same as the maximum outside diameter of the inner tubular element, a last conical member fastened to the outer casing element, said last conical member having its maximum outer diameter substantially the same as the inside diameter of the outer casing element, each said conical member after the first having its minimum internal diameter substantially the same as the maximum outer diameter of the next smaller said conical member, said conical members assembled in order of diameter with the respective tapers running -alternately in opposite directions, each succeeding conical member fastened to the next with the respective substantially equal diameter portions in contact with one another, said fastenings being vacuum tight.

5. Apparatus according to claim 3, in which the said inner tubular element is composed of Invar.

6. A vacuum jacketed conduit extending along a longitudinal axis comprising adjacent unit sections each having an imperforate unitary rigid inner tubular element composed of a substance substantially free from thermal expansion over a temperature range ex-tending from ambient temperature to the widely different temperature of a fluid to be carried by said conduit member, whereby said inner element is substantially constant in length whether heated or cooled within said temperature range, an outer casing element spaced from and of substantially the same length as said inner element, said casing element surrounding said inner element and being su-bstantially c-oextensive in length therewith, said inner and outer elements of each unit section terminating substantially coplanarly at the ends, rand substantially rigid imperforate combined spacing and closure means of effectively low thermal transmission proper-ties fastened to each end of said inner element and the -corresponding end of the said outer element of each adjacent unit section so as to fasten together said inner and outer element in substantially fixed spaced relation to each other and so as to seal the space between said inner and outer element, said spacing and closure means comprising a corrugated member having at least one corrugati-on, extending along said longitudinal axis the maximum depth along said longitudinal axis of corrugation of said corrugation being at least sever-al times as great as the maximum radial distance across said corrugation, thereby providing a relatively long path in order to minimize transfer of heat by conduction from said outer casing element to said inner tubular element, said space being evacuated so as to provide a vacuum therein, said spacing and closure means defining a longitudinally exteriorly facing cavity at each end of each said unit section, insulating material disposed in each exteriorly facing cavity, compressible sealing means connected to opposite ends of said inner element of each unit section to effect a seal between adjacent inner tubular elements of adjacent unit sections, and attachment means connected to the ends of the outer casing element of each unit section for pressing said inner tubular elements of adjacent unit sections as well as the outer casing elements of adjacent unit sections together in end to end relation, whereby a number of said unit sections may be joined and a single unit section can -be removed from a line of said unit sections.

7. In a vacuum jacketed conduit extending along a longitudinal axis in combination, a plurality of ladjacent lengths of fluid carrying imperforate inner tubular elements in end to end relation and a plurality of adjacent lengths of outer casing elements in end to end relation surrounding said lengths of inner tubular elements, each said inner element being of substantially the same length as the youter element which surrounds it, said lengths of inner and outer elements theresurrounding terminating substantially coplanarly at the ends, releasable fluidtight sealing means positioned substantially between and connected to adjacent ends of successive lengths of inner tubular element, means connected to the adjacent ends of the lengths of Kouter casing element to press said adjacent lengths of outer casing together, and rigid imperforate combined spacing and vacuum sealing means attached to`each length of inner element and the surrounding length of outer casing element at the ends of said lengths,l

said spacing and vacuum sealing means defining a substantially fixed space between said lengths of inner and outer element, a vacuum between said lengths of inner element and outer element within said fixed space, said spacing and vacuum sealing means comprising a corrugated member extending along said longitudinal axis of more than one corrugation, at least one corrugation of axial length along said longitudinal axis at least several times as great .as the maximum radial distance across said oorrugation, thereby providing a relatively long path in order to minimize transfer of heat by conduction from said length of outer element t0 Said length of inner element,

said spacing and vacuum sealing means defining a longitudinally exteriorly facing cavity at each end of each length of inner element and the surrounding length of outer casing element, compressible heat insulating and sealing material filling and slightly protruding from said cavity, whereby when said 'adjacent lengths of outer casing elements are pressed together (l) the said sealing means is compressed by pressure transmitted from said outer casing elements through said spacing and vacuum sealing means to said inner elements to actuate the releasable fluid-tight sealing means to form a releasable fluid-tight seal between the adjacent lengths of inner tubular elements and (2) the sealing material is compressed between the surfaces of said rigid support means forming a seal between adjacent lengths of outer and inner casing elements.

8. A vacuum jacketed fluid conduit comprising adjacent unit sections each having 4an imperforate inner fluid carrying tubular element and an outer casing element spaced from and surrounding said inner tubular element, said outer casing and inner tubular elements terminating in substantially coplanar end faces at each end of a said unit section, flanges -connected to each end of the inner tubular element of each said unit section for cooperating with opposing flanges of adjacent unit section, a ring-shaped sealing member, said adjacent flanges releasably comprising therebetween said ringshaped sealing member, substantially rigid imperforate combination spacing and vacuum sealing means fastened to and extending between the outer casing element and inner tubular element of each unit section at each end thereof enclosing a space, a vacuum between said inner and outer element in said sp-ace, said fastenings being vacuum tight, said last mentioned means providing a relatively long path from said outer casing element to said inner tubular element, said last-mentioned means defining `a longitudinally exteriorly facing cavity at each end of said unit section, compressible heat insulating material substantially filling and slightly protruding from said cavity, and clamping means attached at the ends of the outer casing element of each unit section to draw together adjacent outer casing elements of adjacent unit sections, thereby pressing together adjacent fillings of said compressible heat insulating materi-al to form a substantially air-tight joint between adjacent unit sections, while simultaneously, due to the rigidity of the said spacing means, compressing the said ring-shaped sealing member between said flanges on adjacent inner tubular elements of adjacent unit sections to form a releasable fluidtight seal between said adjacent inner tubular elements.

References Cited by the Examiner UNITED STATES PATENTS 226,834 4/1880` Brosius 13S-148 2,419,278 4/1947 Motsenbocker 138-149 X 2,423,213 7/1947 Weber 285-47 2,451,146 10/1948 Baker et al. 13S-149 `2,807,563 9/1957 Waite et al. 138-148 X 2,841,203 7/1958 Gronemeyer 138-148 X 2,924,245 2/ 1960 Wilson 13S-149 FOREIGN PATENTS 211,397 2/ 1959 Australia.

OTHER REFERENCES Advances in Cryogenic Engineering, vol. 4, distributed by Plenum Press Inc. New York (1960), K. D. Timmerhaus, editor, pages 326-334.

LAVERNE D. GEIGER, Primary Examiner.

H, ARTIS, Assistant Examiner. 

1. A VACUUM JACKETED CONDUIT EXTENDING ALONG A LONGITUDINAL AXIS FOR CARRYING A FLUID OF TEMPERATURE SUBSTANTIALLY DIVERGENT FROM AMBIENT COMPRISING ADJACENT UNIT SECTIONS EACH HAVING AN IMPERFORATE UNITARY RIGID INNER TUBULAR ELEMENT, AN OUTER CASING ELEMENT SPACED FROM AND OF SUBSTANTIALLY THE SAME LENGTH AS SAID INNER ELEMENT, SAID CASING ELEMENT SURROUNDING SAID INNER ELEMENT AND BEING SUBSTANTIALLY COEXTENSIVE IN LENGTH THEREWITH, SAID INNER AND OUTER ELEMENTS TERMINATING SUBSTANTIALLY COPLANARLY AT THE ENDS, AND SUBSTANTIALLY RIGID IMPERFORATE COMBINED SPACING AND CLOSURE MEANS OF EFFECTIVELY LOW THERMAL TRANSMISSION PROPERTIES FASTENED TO EACH END OF SAID INNER ELEMENT AND THE CORRESPONDING END OF THE SAID OUTER ELEMENT SO AS TO FASTEN TOGETHER SAID INNER AND OUTER ELEMENT IN SUBSTANTIALLY FIXED SPACED RELATION TO EACH OTHER AND SO AS 